He said: “After another winter of inflation-busting price hikes, the rising cost of energy is already one of the top financial concerns for hard-pressed households.

“The Government should ensure consumers are properly protected from unaffordable misery generated by today’s broken energy market, and give people confidence that they are not writing the energy industry a blank cheque for years to come.”

Consumer Focus chief executive Mike O’Connor said: “We need to invest but we also need to think about how we protect the most vulnerable consumers who can least afford higher prices.

“In the long term the best hope is more energy efficient homes.

"We need to do more to ensure our homes do not leak energy and we are calling on Government to use the funds they raise in carbon taxes to insulate our houses to modern standards, saving the poorest in society money on their bills, as well cutting carbon emissions and creating jobs.

“With six million households in fuel poverty, rising to over nine million by 2016, and an increasing proportion of our incomes being spent on essential items like energy, this latest news, while not surprising, is chilling.”

Ofgem claimed it had been warning the Government of the impending supply crisis since 2009, but said the financial crisis set back plans to get alternative power sources up and running.

The banking meltdown had a major impact on the Government’s ability to pay for schemes such as wind power and nuclear, according to Mr Buchanan.

Responding to Mr Buchanan’s comments, Angela Knight, chief executive of Energy UK, the industry’s trade body, said the authorities should “get on with exploring the options for UK shale gas reserves to help energy security and focus on the affordability of energy to households and the competitiveness of British industry”.

The Government said it was acting to prevent any possible “looming energy gap”.

A spokesman for the Department of Energy and Climate Change said: “Our energy system faces significant challenges over coming years, including the closure of around one-fifth of our ageing power stations, so, as Ofgem highlights, we cannot afford to be complacent and may face a looming energy gap.

“The reforms we are making to the electricity market through the Energy Bill and through our gas generation strategy are aimed at plugging this gap in order to keep the lights on.”

Caroline Flint MP, Labour’s Shadow Energy and Climate Change Secretary, said: “With warnings that Britain could become more reliant on expensive energy imports it is more important than ever that we have an energy market that delivers fair prices and works in the public interest.

“Labour has set out plans to break the dominance of the energy giants, open up the energy market, protect vulnerable customers from being ripped off and create a tough new energy regulator with the power to force energy companies to pass on savings to consumers.

“We must also prioritise making Britain’s homes better insulated and more energy